As the demand for laboratory-bred rhesus monkeys increases, it becomes crucial to manage our populations more effectively in an effort to optimize physical and psychological health, and ultimately production of sufficient numbers of high-quality animals for research purposes. At all primate facilities, there Ire animals that display poor health outcomes (eg, chronic diarrhea), and impaired behavioral, social, and reproductive outcomes (e.g., stereotypes, self-biting, poor social adaptation, poor maternal behavior), while other animals display none of these problems. What accounts for such individual variation? Two decades of psychobiological research with rhesus macaques have documented the existence of stable individual differences in the organization of behavior and physiology. These differences in biobehavioral organization arise from a number of sources, are detectable at an early age, and can persist throughout life. We propose that individual differences in biobehavioral organization (temperament, stress reactivity, personality) are an important contributor to variability in adaptation that is seen in primate colonies. At the CNPRC, we have successfully implemented a colony-wide assessment program based on this body of research. In the current proposal, we aim to continue this program, and to follow-up on the animals that have been enrolled in the program since 2001 by correlating our infancy measures with measures relating to psychological and physical health that are associated with colony management procedures such as relocations, group formations and indoor pairing. The goal of this analysis is to identify risk factors for negative outcomes and to use this information prospectively in colony management. Information on biobehavioral organization will also be made available to investigators who may wish to select animals with specific, defined characteristics for their research projects. Finally, an important aim is to identify more easily obtainable measures that personnel at other primate facilities might adopt that retain the predictive power of the to-be-identified risk factors identified by our more elaborate assessment program. Quantitative application of the solid research base in nonhuman primate psychobiology to colony management is a novel and innovative aspect of this proposal, and reflects a unique blending of goals between colony management and psychobiological science that is, we believe, unique in the NPRC system.